2,428 research outputs found
Consistent Construction of Perturbation Theory on Noncommutative Spaces
We examine the effect of non-local deformations on the applicability of
interaction point time ordered perturbation theory (IPTOPT) based on the free
Hamiltonian of local theories. The usual argument for the case of quantum field
theory (QFT) on a noncommutative (NC) space (based on the fact that the
introduction of star products in bilinear terms does not alter the action) is
not applicable to IPTOPT due to several discrepancies compared to the naive
path integral approach when noncommutativity involves time. These discrepancies
are explained in detail. Besides scalar models, gauge fields are also studied.
For both cases, we discuss the free Hamiltonian with respect to non-local
deformations.Comment: 22 pages; major changes in Section 3; minor changes in the
Introduction and Conclusio
Jurisprudence That Necessarily Embodies Moral Judgment: The Eighth Amendment, Catholic Teaching, and Death Penalty Discourse
The article compares the U.S. Jurisprudence with the death penalty teaching of the Catholic Church through a court case of Patrick Kennedy v. Louisiana Supreme Court. It focuses on the Eighth Amendment Jurisprudence and argues on the translated approach of Catholic Church to advance the death penalty discourse. The article also discusses moral judgment embodied by the Eighth Amendment Jurisprudence
Coherent motion of stereocilia assures the concerted gating of hair-cell transduction channels
The hair cell's mechanoreceptive organelle, the hair bundle, is highly
sensitive because its transduction channels open over a very narrow range of
displacements. The synchronous gating of transduction channels also underlies
the active hair-bundle motility that amplifies and tunes responsiveness. The
extent to which the gating of independent transduction channels is coordinated
depends on how tightly individual stereocilia are constrained to move as a
unit. Using dual-beam interferometry in the bullfrog's sacculus, we found that
thermal movements of stereocilia located as far apart as a bundle's opposite
edges display high coherence and negligible phase lag. Because the mechanical
degrees of freedom of stereocilia are strongly constrained, a force applied
anywhere in the hair bundle deflects the structure as a unit. This feature
assures the concerted gating of transduction channels that maximizes the
sensitivity of mechanoelectrical transduction and enhances the hair bundle's
capacity to amplify its inputs.Comment: 24 pages, including 6 figures, published in 200
Truss Parametrization of Topology Optimization Results with Curve Skeletons and Meta Balls
Truss-like shapes can occur in topology optimization described by an assembly of finite elements or its boundary represented as a polygon mesh. Such shape description does not cover a common engineering parametrization like the lines of a frame structure and its corresponding cross-section. This article addresses the truss-parametrization of such optimization using curve skeletons and Meta Balls. While the curve skeleton is common in the truss-parametrization, including Meta Balls can lead to an overall implicit and smooth shape description
Control of Silica Dust in Slate Milling Operations
The Mine Safety and Health Administration (MSHA) conducted a study to assess the present state of technology used for controlling employees\u27 respirable silica-bearing dust exposures during dimension slate milling operations. For this study, twelve slate milling operations were visited and various measurements were taken and observations made. These measurements and observations included exhaust and room airflow, types of enclosures, water usage, and building volumes for each of the milling processes. These mills usually employed between five and twenty people. From the study, general guidelines were developed from the best practices observed and can be used at the various sawing, splitting, trimming, and drilling operations throughout the industry
Effects of topology optimization in multimaterial 3D bioprinting of soft actuators
Recently, there has been a proliferation of soft robots and actuators that exhibit improved capabilities and adaptability through three-dimensional (3D) bioprinting. Flexibility and shape recovery attributes of stimuli-responsive polymers as the main components in the production of these dynamic structures enable soft manipulations in fragile environments, with potential applications in biomedical and food sectors. Topology optimization (TO), when used in conjunction with 3D bioprinting with optimal design features, offers new capabilities for efficient performance in compliant mechanisms. In this paper, multimaterial TO analysis is used to improve and control the bending performance of a bioprinted soft actuator with electrolytic stimulation. The multimaterial actuator performance is evaluated by the amplitude and rate of bending motion and compared with the single material printed actuator. The results demonstrated the efficacy of multimaterial 3D bioprinting optimization for the rate of actuation and bending
Identifikasi Pengaruh Penggunaan Heatsink Terhadap Keluaran Modul Surya
Panas matahari yang diserap oleh modul surya dapat menaikkan suhu dan menurunkan tegangan keluarannya. Upaya penurunan suhu modul surya agar dalam kondisi standar diperlukan untuk menjaga agar kinerjanya tetap optimal. Pemasangan bahan penyerap panas seperti heatsink merupakan salah satu metode yang dapat digunakan sebagai upaya mendinginkan modul surya. Heatsink mampu mengurangi suhu rata-rata modul surya hingga 2,43°C dan meningkatkan tegangan keluaran rata-rata modul surya hingga 2,23 Volt. Kondisi ini dapat dilihat dari rata-rata tegangan output Voc modul surya yang ditambahkan heatsink dapat mencapai tegangan rata- rata 20,76 Volt dibandingkan dengan modul tanpa penambahan heatsink 18,52 Volt. Disimpulkan bahwa penambahan bahan penyerap panas berupa heatsink lebih efektif menurunkan suhu modul surya dari pada tanpa menggunakan heatsink
Full oxide heterostructure combining a high-Tc diluted ferromagnet with a high-mobility conductor
We report on the growth of heterostructures composed of layers of the
high-Curie temperature ferromagnet Co-doped (La,Sr)TiO3 (Co-LSTO) with
high-mobility SrTiO3 (STO) substrates processed at low oxygen pressure. While
perpendicular spin-dependent transport measurements in STO//Co-LSTO/LAO/Co
tunnel junctions demonstrate the existence of a large spin polarization in
Co-LSTO, planar magnetotransport experiments on STO//Co-LSTO samples evidence
electronic mobilities as high as 10000 cm2/Vs at T = 10 K. At high enough
applied fields and low enough temperatures (H < 60 kOe, T < 4 K) Shubnikov-de
Haas oscillations are also observed. We present an extensive analysis of these
quantum oscillations and relate them with the electronic properties of STO, for
which we find large scattering rates up to ~ 10 ps. Thus, this work opens up
the possibility to inject a spin-polarized current from a high-Curie
temperature diluted oxide into an isostructural system with high-mobility and a
large spin diffusion length.Comment: to appear in Phys. Rev.
Control of a SiC 2.5 MHz resonant full-bridge inverter for inductively driven plasma
The electronic ballast of an inductively driven plasma faces a mostly inductive, variable load impedance. The SiC full-bridge inverter uses the inductive behavior to achieve zero-voltage-switching and a switching frequency of 2.5 MHz, at 3.9 kVA and 764W in the plasma. The control is realized on a modern, small TI Piccolo microcontroller with a high-resolution PWM module and compensates for the variable load impedance. We present design and experimental results of a 2.5 MHz inverter for inductively driven plasma without the need for a large FPGA controller
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